Microscopic polymer cups by electrospinning

Polymer solution above a critical concentration is generally required for making a uniform diameter nano fiber by electrospinning. Below this critical concentration, nanofibers are accompanied with bead formation and, therefore, this concentration region has not received much attention. A systematic investigation reveals that unique particle shapes can be obtained by electroprocessing within this lower concentration range. Several micrometer diameter poly(methyl methacrylate) PMMA cups with wall thickness in the 200–800 nm range and 50–300 nm size pores have been obtained by electroprocessing in high dielectric constant solvents.